The present invention relates to electromechanical devices and, more particularly, to microelectromechanical devices.
Microelectromechanical systems (MEMS) have recently been developed as alternatives for conventional electromechanical devices such as relays, actuators, valves and sensors. MEMS devices are potentially low cost devices, due to the use of microelectronic fabrication techniques. New functionality may also be provided because MEMS devices can be much smaller than conventional electromechanical devices.
Many applications of MEMS technology use MEMS actuators. For example, U.S. Pat. No. 5,923,798 to Aksyuk et al. discloses a micro-machined optical switch that utilizes an electrostatically-driven actuator comprising hinged plates. In particular, the ""798 patent discloses an xe2x80x9cin-planexe2x80x9d optical switch having an actuator formed by two vertically-oriented electrodes and linkage from the actuator to an optical device. One of the electrodes is movable and the other is fixed. The optical device is positioned in close proximity to two spaced optical fibers that are aligned to optically communicate with one another. The optical device is movable in and out of an optical path defined by the optical cores of the optical fibers upon application of a horizontal or in-plane displacement of sufficient magnitude. As a voltage is applied across the electrodes by a controlled voltage source, the movable electrode swings towards the fixed electrode. The substantially horizontal displacement of the movable electrodes is transferred, by the linkage, to the optical device. As a result, the optical device moves horizontally or in-plane along a path that places it in, or out of, the optical path as a function of the back and forth oscillatory-type motion of the movable electrode.
Unfortunately, conventional optical switches such as those described in the ""798 patent may require the continuous presence of an electrostatic potential across a pair of electrodes to maintain the optical device in a blocking position within the optical path. Accordingly, not only will the switch need to be continuously powered, but an interruption of power to the switch may cause the switch to reset. Thus, notwithstanding conventional microelectromechanical devices, there continues to be a need for improved microelectromechanical devices having reduced power consumption requirements and reduced susceptibility to power interruptions.
It is therefore an object of the present invention to provide improved microelectromechanical devices.
It is another object of the present invention to provide microelectromechanical optical devices having optical shutters therein that can block and/or redirect optical beams.
It is still another object of the present invention to provide microelectromechanical optical devices having nonvolatile characteristics.
These and other objects, advantages and features of the present invention may be provided by preferred microelectromechanical optical devices that include a substrate having first and second optical fibers thereon. The first and second optical fibers are positioned so that an end of the first optical fiber faces an end of the second optical fiber. An optical shutter is also provided. This optical shutter is mechanically coupled to a first plurality of arched beams that are supported at opposing ends by support structures which may be mounted on the substrate. A second plurality of arched beams are also provided on a first side of the optical shutter. These arched beams are also supported at opposing ends by support structures. According to a preferred aspect of the present invention, a first brake member is provided that is coupled to the second plurality of arched beams. This first brake member contacts and restricts the optical shutter from moving in the xc2x1y-direction when the second plurality of arched beams are relaxed, but releases the optical shutter when the second plurality of arched beams move in the xe2x88x92x direction. This ability to restrict movement of the optical shutter when the second plurality of arched beams are relaxed provides a degree of nonvolatile position retention. A third plurality of arched beams are also preferably provided on a second side of the optical shutter. A second brake member, which is coupled to the third plurality of arched beams, also contacts and restricts the shutter member from moving in the xc2x1y direction when the third plurality of arched beams are relaxed, but releases the optical shutter when the third plurality of arched beams move in the +x direction.
The first plurality of arched beams, which are mechanically coupled to the optical shutter, can be used to control movement of the optical shutter into a gap extending between the ends of the first and second optical fibers. In this position, the optical shutter can operate to limit the degree of optical coupling between the first and second optical fibers and can even be positioned to block all light from being transferred from one fiber to the other. The first and second brake members and the second and third pluralities of arched beams may collectively form a xe2x80x9cnormally-lockedxe2x80x9d brake assembly where the preferably diametrically opposing ends of the first and second brake members contact and restrict movement of the optical shutter or other movable element when the second and third pluralities of arched beams are in relaxed states.